Laser processing apparatus

ABSTRACT

A laser processing apparatus 3 includes: a laser head H; a conveying device 4 that conveys a workpiece W; a head driving mechanism that moves the laser head H; a dust collecting box 60 that moves below the workpiece W and follows the laser head H such that the dust collecting box 60 is disposed below the laser head H; an outer support roller 81 and an inner support roller 82 that are provided at an opening 61 of the dust collecting boz 60 and are rotatable around an axis parallel to a width direction orthogonal to a conveying direction Fy; and a counter roller 9 that rotates the outer support roller 81 in synchronization with a conveying operation of the workpiece W by the conveying device 4. The counter roller 9 transmits motive power of the conveying device 4 as a belt conveyor to the outer support roller 81.

This application is based on and claims the benefit of priority fromJapanese Patent Application No. 2020-031336, filed on 27 Feb. 2020, thecontent of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a laser processing apparatus. Morespecifically, the present invention relates to a laser processingapparatus for cutting plate material by moving a laser irradiation unitabove the plate material which is conveyed by a conveying device.

Related Art

Conventionally, a laser processing apparatus has been proposed whichcuts plate material into a desired shape to prepare a blank material bymoving a laser head which irradiates a laser beam above the platematerial fed by a conveying device.

In such a laser processing apparatus, a scrap box moving below the platematerial and following a laser head collects a spatter generated byapplying the laser beam to the plate material (refer to JapaneseUnezamined Patent Application, Publication No. 2000-153427).Furthermore, in order to prevent the lower surface of the plate materialfrom being damaged when moving the scrap box to follow the laser head, aroller may be provided at the opening of the scrap box to support thelower surface of the plate material by this roller. This allows theroller to support this plate material while rolling on the lower surfaceof the plate material when moving the scrap box along the conveyingdirection, and thus it is possible to prevent the damage on the lowersurface of the plate material.

-   Patent Document 1: Japanese Unexamined Patent Application,    Publication No. 2000-153427

SUMMARY OF THE INVENTION

However, in a case in which such a roller is provided at the opening ofthe scrap box, when reversing the moving direction of the scrap boxwhile the conveying device is conveying the plate material in theconveying direction, since inertia causes the roller to keep rolling,the position of the plate material in contact with this roller may beshifted in the original moving direction. For this reason, there is riskof cutting processing of the plate material by a laser beam with goodprecision no longer being possible.

It is an object of the present invention to provide a laser processingapparatus capable of suppressing dislocation of a plate material whenreversing a moving direction of a dust collecting unit, while preventingthe plate material from being damaged due to the movement of the dustcollecting unit.

A first aspect of the present invention relates to a laser processingapparatus (for example, a laser processing apparatus 3 described later)including: a laser irradiation unit (for example, a laser head Hdescribed later); a conveying device (for example, a conveying device 4described later) that conveys a plate material (for example, a workpieceW described later) along a conveying direction (for example, a conveyingdirection Fy described later); a drive unit (a head driving mechanism 5described later) that moves the laser irradiation unit above the platematerial; a dust collecting unit (for example, a dust collecting box 60described later) that moves below the plate material and follows thelaser irradiation unit such that the dust collecting unit is disposeddirectly below the laser irradiation unit, and a roller (for example, anouter support roller 81 and an inner support roller 82 described later)that is provided at an opening (for example, an opening 61 describedlater) of the dust collecting unit and is rotatable around an axisparallel to a width direction (for example, a width direction Fxdescribed later) orthogonal or substantially orthogonal to the conveyingdirection, and the laser processing apparatus further includes a drivingmechanism (for example, a counter roller 9 described later) that rotatesthe roller in synchronization with a conveying operation of the platematerial by the conveying device.

According to a second aspect of the present invention, it is preferablethat the conveying device is a belt conveyor, and the driving mechanismincludes a power transmission mechanism (for example, a counter roller 9described later) that transmits motive power of the belt conveyor to theroller.

According to a third aspect of the present invention, it is preferablethat the belt conveyor includes a plurality of belt rollers (forexample, belt rollers 41, 42, 43, and 44 described later) that arerotatable around the axis parallel to the width direction, and astrip-shaped belt (for example, a belt 45 described later) stretchedover the plurality of belt rollers, and the power transmission mechanismincludes a counter roller (for example, a counter roller 9) that isrotatable around the axis parallel to the width direction, and an outerperipheral surface of the counter roller is in contact with the beltroller or the belt and the roller.

According to a fourth aspect of the present invention, it is preferablethat a non-contact support portion (for example, a non-contact supportpad 7 described later)) is provided at the opening, and the non-contactsupport portion suctions a lower surface of the plate material toward asuction surface (for example, a suction surface 71 described later) andsupports the plate material without bringing the lower surface of theplate material and the suction surface into contact with each other, theopening includes an upstream-side opening edge (for example, anupstream-side opening edge 64 described later) extending along the widthdirection, and a downstream-side opening edge (for example, adownstream-side opening edge 65 described later) extending along thewidth direction on a downstream side of the upstream-side opening edgein the conveying direction in a plan view, and the roller includes aplurality of rollers, and the non-contact support portion includes aplurality of non-contact support portions, and one or more of therollers and one or more of the non-contact support portions are providedalternately along the width direction at each of the upstream-sideopening edge and the downstream-side opening edge.

(1) A laser processing apparatus according to the present inventionincludes: a conveying device that conveys a plate material; a drive unitthat moves the laser irradiation unit above the plate material; a dustcollecting unit that moves below the plate material and follows thelaser irradiation unit such that the dust collecting unit is disposeddirectly below the laser irradiation unit; and a roller that is providedat an opening of the dust collecting unit and is rotatable around anaxis parallel to a width direction. With such a configuration, whenmoving the dust collecting unit along the conveying direction, theroller supports the plate material while rolling on the lower surface ofthe plate material. Therefore, it is possible to prevent the damage onthe lower surface of the plate material. Furthermore, the laserprocessing apparatus according to the present invention includes adriving mechanism that rotates the roller in synchronization with aconveying operation of the plate material by the conveying device. Withsuch a configuration, even when reversing the moving direction of thedust collecting unit while conveying the plate material along theconveying direction by the conveying device, the roller no longer keepsrolling due to inertia in the original moving direction. Therefore, itis possible to prevent dislocation of the plate material in contact withthe roller. With such a configuration, it is possible to perform cuttingprocessing with a laser beam irradiated from the laser irradiation unitwith good precision.

(2) In the present invention, a belt conveyor is used as the conveyingdevice conveying the plate material, and the power transmissionmechanism transmits motive power of the belt conveyor to the roller.With such a configuration, it is possible to rotate the roller insynchronization with the conveying operation of the plate materialwithout adding any actuator for driving the roller.

(3) In the present invention, the counter roller that is rotatablearound the axis parallel to the width direction, and of which an outerperipheral surface is in contact with the belt roller or the belt andthe roller transmits the motive power of the belt conveyor to theroller. With such a configuration, it is possible to prevent thedislocation of the plate material when reversing the moving direction ofthe dust collecting unit with a simple configuration.

(4) In the present invention, one or more of the rollers and one or moreof the non-contact support portions are provided alternately along thewidth direction at each of the upstream-side opening edge and thedownstream-side opening edge of the dust collecting unit. When theplurality of non-contact support units are provided at both theupstream-side opening edge and the downstream-side opening edge of thedust collecting unit as described above, the lower surface of the platematerial is pressed against the outer peripheral surfaces of therollers. Therefore, while the waviness of the portion of the platematerial to which the laser beam is irradiated is removed, thedislocation of the plate material when reversing the moving direction ofthe dust collecting unit becomes significant. In this regard, in thepresent invention, the driving mechanism causes the roller to rotate insynchronization with the conveying operation of the plate material bythe conveying device as described above. With such a configuration, itis possible to prevent dislocation of the plate material when reversingthe moving direction of the dust collecting unit while removing thewaviness of the plate material. Therefore, according to the presentinvention, it is possible to quickly move the laser irradiation unit andthe dust collecting unit while conveying the plate material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the configuration of a laser processingsystem according to an embodiment of the present invention;

FIG. 2 is a perspective view showing a schematic configuration of alaser processing apparatus;

FIG. 3 is a plan view of a dust collecting box from a workpiece side;

FIG. 4 is a cross-sectional view taken along the line IV-IV intersectingthe pair of support rollers in FIG. 3 ;

FIG. 5 is a cross-sectional view taken along the line V-V intersectingthe non-contact support pad in FIG. 3 ;

FIG. 6A is a perspective view of the non-contact support pad from asuction surface side;

FIG. 6B is a cross-sectional view of a non-contact support pad 7 alongthe line VI-VI in FIG. 6A;

FIG. 7 is an enlarged view of an upstream-side opening edge and anupstream cover of FIG. 5 ; and

FIG. 8 is a view of a lower surface of the upstream cover seen from aside of the non-contact support pad.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a laser processing apparatus 3 according to an embodimentof the present invention will be described with reference to thedrawings.

FIG. 1 is a diagram showing a configuration of a laser processing system1. The laser processing system 1 includes a leveler device 2 thatremoves waviness of a workpiece W which is a plate material fed from aroll-shaped coil material C and linearly straightens the workpiece W,and a laser processing apparatus 3 for cutting the workpiece W linearlystraightened by the leveler device 2 with a laser beam. The workpiece Wis, for example, a plate material made of an aluminum alloy or a steelplate; however, the present invention is not intended to be limitedthereto.

The leveler device 2 includes a plurality of upper rollers 21 providedon the upper side in the vertical direction with respect to theworkpiece W to be fed from the coil material C (in the example of FIG. 1, three pieces), and a plurality of lower rollers 22 provided across theworkpiece W with respect to these upper rollers 21 (in the example ofFIG. 1 , four pieces). The rotation axes of the upper rollers 21 and therotation axes of the lower rollers 22 are provided parallel to oneanother. These lower rollers 22 and upper rollers 21 are providedalternately along the feeding direction of the workpiece W. The levelerdevice 2 extends the workpiece W fed from the coil material C to be flatby the plurality of upper rollers 21 and the plurality of lower rollers22, thereby removing the waviness of the plate material and linearlystraightening the workpiece W. The workpiece W straightened linearly bythe leveler device 2 is fed to the laser processing apparatus 3.

FIG. 2 is a perspective view showing a schematic configuration of alaser processing apparatus 3. The laser processing apparatus 3 includesa conveying device 4 for conveying the workpiece W along a conveyingdirection Fy, a laser head H for generating a laser beam and irradiatingthe workpiece W with the laser beam, a head driving mechanism 5 formoving the laser head H above the workpiece W fed along the conveyingdirection Fy, and a dust collector 6 for collecting a spatter caused byirradiating the workpiece W with the laser beam.

The conveying device 4 is a belt conveyor, and includes a plurality ofbelt rollers 41, 42, 43, and 44 which are rotatable about an axisparallel to a width direction Fx orthogonal to the conveying directionFy (only four rollers are illustrated in FIG. 2 ), an endlessstrip-shaped belt 45 stretched over these belt rollers 41 to 44, and aroller driving device (not shown) for feeding the belt 45 to thedownstream side along the conveying direction Fy by rotating any of theplurality of belt rollers 41 to 44 (for example, the first belt roller41).

The first to fourth belt rollers 41 to 44 are provided in this orderfrom the upstream side to the downstream side along the conveyingdirection Fy. Between the second belt roller 42 and the third beltroller 43, a dust collecting box 60 to be described later is provided.Furthermore, the belt 45 is stretched over the first to fourth beltrollers 41 to 44 so as to avoid the dust collecting box 60. Furthermore,the second belt roller 42 and the third belt roller 43 are slidable tothe downstream side or to the upstream side along the conveyingdirection Fy together with the dust collecting box 60 by a box drivingmechanism to be described later.

The head driving mechanism 5 includes an X-axis rail 51 extending alongthe width direction Fx above the belt 45, and a Y-axis rail 52 extendingalong the conveying direction Fy at the side portion of the belt 45. TheX-axis rail 51 slidably supports the laser head H along its extendingdirection (i.e., the width direction Fx). The Y-axis rail 52 slidablysupports the X-axis rail 51 along its extending direction (i.e., theconveying direction Fy). This allows the head driving mechanism 5 tomove the laser head H along the conveying direction Fy and the widthdirection Fx above the workpiece W conveyed by the conveying device 4.

The dust collector 6 includes a box-shaped dust collecting box 60extending along the width direction Fx, and a box driving mechanism (notshown) for moving the dust collecting box 60 along the conveyingdirection Fy.

The dust collecting box 60 is provided between the second belt roller 42and the third belt roller 43 below the workpiece W. A rectangularopening 61 extending along the width direction Fx in a plan view isprovided above the dust collecting box 60. The spatter caused byirradiating the workpiece W with a laser beam from the laser head H iscollected in the dust collecting box 60 through the opening 61. Thespatter collected in the dust collecting box 60 is appropriatelydischarged from a discharge unit 63 provided on a side cover 62.

The box driving mechanism moves the dust collecting box 60, the secondbelt roller 42, and the third belt roller 43 to follow the movement ofthe laser head H along the conveying direction Fy, such that the opening61 of the dust collecting box 60 is disposed directly below the laserhead H.

FIG. 3 is a plan view of the dust collecting box 60 from the workpiece Wside. As shown in FIG. 3 , in a plan view, the opening 61 of the dustcollecting box 60 has a rectangular shape, and includes an upstream-sideopening edge 64 extending along the width direction Fx, and adownstream-side opening edge 65 extending along the width direction Fxon the downstream side of the upstream-side opening edge 64 in theconveying direction Fy.

The upstream-side opening edge 64 includes a plurality of disk-shapednon-contact support pads 7 (in the example of FIG. 3 , seven pieces) ina plan view, the plurality of support rollers pairs 8 (in the example ofFIG. 3 , six sets) made by a pair of an outer support roller 81 and aninner support roller 82, and a rectangular upstream cover 66 extendingalong the width direction Fx in a plan view.

In the upstream-side opening edge 64, one non-contact support pad 7 andthe pair of the support rollers 8 are provided in rows and alternatelyalong the width direction Fx. It should be noted that FIG. 3 shows acase in which one non-contact support pad 7 and the pair of the supportrollers 8 are provided alternately along the width direction Fx in theupstream-side opening edge 64; however, the present invention is notintended to be limited thereto. Two or more of the non-contact supportpads 7 and two or more sets of the support roller pairs 8 may beprovided alternately along the width direction Fx in the upstream sideopening edge 64.

The downstream-side opening edge 65 includes a plurality of disk-shapednon-contact support pads 7 (in the example of FIG. 3 , seven pieces) ina plan view, a plurality of the pairs of the support rollers 8 (in theexample of FIG. 3 , six sets), and a rectangular downstream cover 67extending along the width direction Fx in a plan view.

In the downstream-side opening edge 65, one non-contact support pad 7and a pair of the support rollers 8 are provided in rows and alternatelyalong the width direction Fx. It should be noted that FIG. 3 shows acase in which one non-contact support pad 7 and the pair of the supportrollers 8 are provided alternately along the width direction Fx in thedownstream-side opening edge 65; however, the present invention is notintended to be limited thereto. Two or more of the non-contact supportpads 7 and two or more sets of the support rollers 8 may be providedalternately along the width direction Fx in the downstream-side openingedge 65.

FIG. 4 is a cross-sectional view taken along a line IV-IV intersectingthe pair of the support rollers 8 in FIG. 3 . The dust collecting box 60is substantially U-shaped in cross-sectional view. At the upstream-sideopening edge 64 of the dust collecting box 60, the outer support roller81 and the inner support roller 82 that are each rotatable about theaxis parallel to the width direction Fx (see FIG. 3 ) are provided inparallel in this order along the conveying direction Fy from theupstream side to the downstream side. Furthermore, at thedownstream-side opening edge 65 of the dust collecting box 60, the innersupport roller 82 and the outer support roller 81 that are eachrotatable about the axis parallel to the width direction Fx are providedin parallel in this order along the conveying direction Fy from theupstream side to the downstream side.

At the upstream cover 66, a plurality of upstream-side roller windows 66a which are each a substantially rectangular opening in a plan view areprovided at predetermined intervals along the width direction Fx (in theexample of FIG. 3 , six pieces). Furthermore, as shown in FIG. 4 , aportion of the outer peripheral surface of the total of six sets of theouter support rollers 81 and the inner support rollers 82 provided atthe upstream-side opening edge 64 is exposed to the side of theworkpiece W through these upstream-side roller windows 66 a. In otherwords, a portion of the outer peripheral surface of the outer supportrollers 81 and the inner support rollers 82 protrudes from the uppersurface of the upstream cover 66 to the side of the workpiece W.Therefore, the lower surface of the workpiece W conveyed along theconveying direction Fy by the conveying device 4 is brought into contactwith the outer peripheral surfaces of these outer support rollers 81 andthe inner support rollers 82. Furthermore, as shown in FIGS. 3 and 4 ,the end of the upstream side and the end of the downstream side alongthe conveying direction Fy of the upstream cover 66 are slightly bentdownwards in the vertical direction, respectively. Therefore, theperipheries of the plurality of sets of the outer support rollers 81 andthe inner support rollers 82 provided on the upstream side opening edge64 are covered by the upstream cover 66.

Furthermore, as shown in FIG. 4 , a counter roller 9 which is rotatableabout the axis parallel to the outer support roller 61 is providedbetween the outer support roller 81 of the upstream-side opening edge 64and the second belt roller 42. The outer peripheral surface of thecounter roller 9 is in contact with the belt 45 and the outer supportroller 81. Therefore, a part of the power for conveying the workpiece Walong the conveying direction Fy in the conveying device 4 as a beltconveyor is transmitted to the outer support roller 81 via the counterroller 9. This allows the outer support roller 81 to rotate insynchronization with the conveying operation of the workpiece W by theconveying device 4. It should be noted that FIG. 4 illustrates a case inwhich the outer peripheral surface of the counter roller 9 is in contactwith the belt 45; however, the present invention is not intended to belimited thereto. The outer peripheral surface of the counter roller 9may be in contact with the outer peripheral surface of the second beltroller 42.

At the downstream cover 67, a plurality of downstream-side rollerwindows 67 a, which are each a substantially rectangular opening in aplan view, are provided at predetermined intervals along the widthdirection Fx (in the example of FIG. 3 , six pieces). Furthermore, asshown in FIG. 4 , a portion of the outer peripheral surface of the total6 sets of the outer support rollers 81 and the inner support rollers 82provided at the downstream-side opening edge 65 is exposed to the sideof the workpiece W through these downstream side roller windows 67 a. Inother words, a portion of the outer peripheral surface of the outersupport roller 81 and the inner support roller 82 protrudes from theupper surface of the downstream cover 67 to the side of the workpiece W.Therefore, the lower surface of the workpiece W conveyed along theconveying direction Fy by the conveying device 4 is brought into contactwith the outer peripheral surfaces of these outer support roller 81 andthe inner support roller 82. Furthermore, as shown in FIGS. 3 and 4 ,the end of the upstream side and the end of the downstream side alongthe conveying direction Fy of the downstream cover 67 are slightly bentdown in the vertical direction, respectively. Therefore, the peripheriesof the plurality of sets of the outer support rollers 81 and the innersupport roller 82 provided at the downstream-side opening edge 65 arecovered by the downstream cover 67.

Furthermore, as shown in FIG. 4 , the counter roller 9 which isrotatable about the axis parallel to the outer support roller 81 isprovided between the outer support roller 81 of the downstream-sideopening edge 65 and the third belt roller 43. The outer peripheralsurface of the counter roller 9 is in contact with the belt 45 and theouter support roller 81. Therefore, a portion of the power for conveyingthe workpiece W along the conveying direction Fy in the conveying device4 as a belt conveyor is transmitted to the outer support roller 81 viathe counter roller 9. This allows the outer support roller 81 to rotatein synchronization with the conveying operation of the workpiece W bythe conveying device 4. It should be noted that FIG. 4 illustrates acase in which the outer peripheral surface of the counter roller 9 is incontact with the belt 45; however, the present invention is not intendedto be limited thereto. The outer peripheral surface of the counterroller 9 may be in contact with the outer peripheral surface of thethird belt roller 43.

FIG. 5 is a cross-sectional view taken along the line V-V intersectingthe non-contact support pad 7 in FIG. 3 . The disk-shaped non-contactsupport pad 7 in a plan view is respectively provided at theupstream-side opening edge 64 and the downstream-side opening edge 65 ofthe dust collecting box 60.

FIG. 6A is a perspective view of the non-contact support pad 7 from aside of a suction surface 71. FIG. 6B is a cross-sectional view of thenon-contact support pad 7 along the line VI-VI in FIG. 6A.

The non-contact support pad 7 has a cylindrical shape. An annular groove73 in a plan view is provided at an outer peripheral edge 72 of thesuction surface 71 of the non-contact support pad 7. A plurality ofnozzle holes 74 (in the example of FIG. 6A, four) are provided in thegroove 73. An air supply hole 76 to which an air pump (not shown) isconnected is provided at substantially the center of the bottom surface75 opposite to the suction surface 71 of the non-contact support pad 7.Furthermore, as shown in FIG. 6B, an air flow path 77 for communicatingthe air supply hole 76 and the plurality of nozzle holes 74 is providedinside the non-contact support pad 7.

Therefore, in the non-contact support pad 7, when supplying aircompressed by the air pump to the air supply hole 76, the swirling flowof air extending radially outward as indicated by a broken line arrow inFIG. 6A is generated from the plurality of nozzle holes 74 provided inthe groove 73 of the suction surface 71. Therefore, when the workpiece Wexists on the side of the suction surface 71, a negative pressure isgenerated between the suction surface 71 and the workpiece W by theBernoulli effect, and the workpiece W is sucked toward the suctionsurface 71 by the negative pressure. As described above, the non-contactsupport pad 7 utilizes the negative pressure generated between the lowersurface of the workpiece W and the suction surface 71 when the swirlingflow of air from the nozzle hole 74 is ejected, thereby suctioning thelower surface of the workpiece W toward the suction surface 71, andsupporting the workpiece W without bringing the lower surface of theworkpiece W and the suction surface 71 into contact with each other.

FIG. 7 is an enlarged view of the upstream-side opening edge 64 and theupstream cover 66 of FIG. 5 . It should be noted that the configurationsof the downstream-side opening edge 65 and the downstream cover 67 aresubstantially the same as in FIG. 4 , and thus, illustration and adetailed description thereof will be omitted.

As shown in FIG. 7 , the peripheries of the plurality of non-contactsupport pads 7 provided at the upstream-side opening edge 64 are coveredby the upstream cover 66. Furthermore, at the upstream cover 66, aplurality of upstream-side support pad windows 66 b (in the example ofFIG. 3 , seven), which are each a disk-shaped opening in a plan view, isprovided at predetermined intervals along the width direction Fx. Thesuction surface 71 of the plurality of non-contact support pads 7provided at the upstream-side opening edge 64 is visible through theupstream-side support pad window 66 b from the side of the workpiece W.The inner diameter of these upstream-side support pad windows 66 b isslightly smaller than the outer diameter of the non-contact support pad7. Therefore, the upstream cover 66 covers a portion of the outerperipheral edge 72 of the non-contact support pad 7.

As described above, the portion of the outer peripheral surface of theouter support roller 81 and the inner support roller 82 protrudes fromthe upper surface of the upstream cover 66 to the side of the workpieceW, while the suction surface 71 of the non-contact support pad 7 isburied from the upper surface of the upstream cover 66. As shown in FIG.7 , a gap 69 is provided between the outer peripheral edge 72 of thenon-contact support pad 7 and the lower surface of the upstream cover66.

FIG. 8 is a view of the lower surface of the upstream cover 66 seen fromthe side of the non-contact support pad 7. As shown in FIG. 8 , aplurality of grooves 66 c extending radially about the suction surfaceof the non-contact support pad 7 are provided at the peripheral edge ofthe upstream-side support pad window 66 b of the lower surface of theupstream cover 66.

Next, a description will be given of a procedure for cutting theworkpiece W by the laser head H while removing the waviness of theworkpiece W in the laser processing apparatus 3 as described above.First, when supplying compressed air to the air supply hole 76 of thenon-contact support pad 7, the swirling flow of air extending radiallyoutward from the nozzle hole 74 provided in the suction surface 71 isgenerated. As shown schematically by a broken line arrow in FIG. 7 , theswirling flow of air flows into the gap 69 (refer to FIG. 7 ) providedbetween the lower surface of the workpiece W and the upper surface ofthe upstream cover 66 (or the downstream cover 67), and between theouter peripheral edge 72 of the non-contact support pad 7 and theupstream cover 66 (or the downstream cover 67), a result of which thenegative pressure is generated between the suction surface 71 and thelower surface of the workpiece W. Furthermore, when the negativepressure is generated between the suction surface 71 and the lowersurface of the workpiece W, the lower surface of the workpiece W issucked toward the suction surface 71, following which the lower surfaceof the workpiece W is pressed against the outer peripheral surfaces ofthe outer support roller 81 and the inner support roller 82, a result ofwhich the waviness of the workpiece W is removed. Therefore, with thelaser processing apparatus 3, by irradiating a laser beam from the laserhead H while removing the waviness of the workpiece W using thenon-contact support pad 7 as described above, it is possible to cut theworkpiece W with high accuracy.

The laser processing apparatus 3 according to the present embodiment hasthe following effects.

(1) The laser processing apparatus 3 includes: the conveying device 4that conveys the workpiece W; the head driving mechanism 5 that movesthe laser head H above the workpiece W; the dust collecting box 60 thatmoves below the workpiece W and follows the laser head H such that thedust collecting box 60 is disposed directly below the laser head H, andthe outer support roller 81 and the inner support roller 82 that areprovided at the opening 61 of the dust collecting box 60 and isrotatable around an axis parallel to the width direction Fx. With such aconfiguration, when moving the dust collecting box 60 along theconveying direction Fy, the support rollers 81 and 82 support theworkpiece W while rolling on the lower surface of the workpiece W.Therefore, it is possible to prevent the damage on the lower surface ofthe workpiece W. Furthermore, the laser processing apparatus 3 furtherincludes the counter roller 9 that rotates the outer support roller 81in synchronization with a conveying operation of the workpiece W by theconveying device 4. With such a configuration, even when reversing themoving direction of the dust collecting box 60 while conveying theworkpiece W along the conveying direction Fy by the conveying device 4,the outer support roller 81 no longer keeps rolling due to inertia inthe original moving direction. Therefore, it is possible to preventdislocation of the workpiece W in contact with the outer support roller81. With such a configuration, it is possible to perform cuttingprocessing with a laser beam irradiated from the laser head H with goodprecision.

(2) In the laser processing apparatus 3, a belt conveyor is used as theconveying device 4 conveying the workpiece W, and the counter roller 9transmits motive power of the belt conveyor to the outer support roller61. With such a configuration, it is possible to rotate the outersupport roller 81 in synchronization with the conveying operation of theworkpiece W without adding any actuator for driving the outer supportroller 81.

(3) In the laser processing apparatus 3, the counter roller 9 that isrotatable around the axis parallel to the width direction Fx, and ofwhich an outer peripheral surface is in contact with the belt rollers 41to 44 or the belt 45 and the outer support rollers 81 transmits themotive power of the belt conveyor to the outer support roller 81. Withsuch a configuration, it is possible to prevent the dislocation of theworkpiece W when reversing the moving direction of the dust collectingbox 60 with a simple configuration.

(4) In the laser processing apparatus 3, one or more of the supportrollers 81 and 82 and one or more of the non-contact support pads 7 areprovided alternately along the width direction Fx at each of theupstream-side opening edge 64 and the downstream-side opening edge 65 ofthe dust collecting box 60. When the plurality of non-contact supportpads 7 are provided at both the upstream-side opening edge 64 and thedownstream-side opening edge 65 of the dust collecting box 60 asdescribed above, the lower surface of the workpiece W is pressed againstthe outer peripheral surfaces of the support rollers 81 and 82.Therefore, while the waviness of the portion of the workpiece W to whichthe laser beam is irradiated is removed, the dislocation of theworkpiece W when reversing the moving direction of the dust collectingbox 60 becomes significant. In this regard, in the laser processingapparatus 3, the counter roller 9 causes the outer support roller 81 torotate in synchronization with the conveying operation of the platematerial by the conveying device 4 as described above. With such aconfiguration, it is possible to prevent dislocation of the workpiece Wwhen reversing the moving direction of the dust collecting box 60 whileremoving the waviness of the workpiece W. Therefore, according to thelaser processing apparatus 3, it is possible to quickly move the laserhead H and the dust collecting box 60 while conveying the workpiece W.

While an embodiment of the present invention has been described above,the present invention is not intended to be limited thereto. Within thespirit of the present invention, the configuration of detailed parts maybe changed as appropriate.

For example, in the above embodiment, the case has been described inwhich the counter roller 9 is used as a power transmission mechanism fortransmitting the power of the conveying device 4 as a belt conveyor tothe upstream-side support roller 81; however, the present invention isnot limited thereto. The power transmission mechanism is not limited tothe counter roller 9, and may be configured by combining components suchas a shaft and a belt.

Furthermore, for example, in the above embodiment, the case has beendescribed in which the counter roller 9 is used as a driving mechanismfor rotating the upstream-side support roller 81 in synchronization withthe conveying operation of the workpiece W by the conveying device 4;however, the present invention is not limited thereto. For example, anactuator for rotating the upstream-side support roller 81 may beprovided to drive this actuator in synchronization with the conveyingoperation by the conveying device 4, thereby rotating the upstream-sidesupport roller 81 in synchronization with the conveying operation of theworkpiece W by the conveying device 4.

What is claimed is:
 1. A laser processing apparatus comprising: a laserirradiation unit; a conveying device that conveys a plate material alonga conveying direction; a drive unit that moves the laser irradiationunit above the plate material; a dust collecting unit that moves belowthe plate material and follows the laser irradiation unit such that thedust collecting unit is disposed directly below the laser irradiationunit; and a roller that is provided at an opening of the dust collectingunit and is rotatable around an axis parallel to a width directionorthogonal or substantially orthogonal to the conveying direction,wherein the laser processing apparatus further comprising a drivingmechanism that rotates the roller in synchronization with a conveyingoperation of the plate material by the conveying device, a non-contactsupport portion is provided at the opening, and the non-contact supportportion suctions a lower surface of the plate material toward a suctionsurface and supports the plate material without bringing the lowersurface of the plate material and the suction surface into contact witheach other, the opening includes an upstream-side opening edge extendingalong the width direction, and a downstream-side opening edge extendingalong the width direction on a downstream side of the upstream-sideopening edge in the conveying direction in a plan view, and the rollerincludes a plurality of rollers, and the non-contact support portionincludes a plurality of non-contact support portions, and one or more ofthe rollers and one or more of the non-contact support portions areprovided alternately along the width direction at each of theupstream-side opening edge and the downstream-side opening edge.
 2. Thelaser processing apparatus according to claim 1, wherein the conveyingdevice comprises a belt conveyor, and the driving mechanism comprises apower transmission mechanism that transmits motive power of the beltconveyor to the roller.
 3. The laser processing apparatus according toclaim 2, wherein the belt conveyor includes a plurality of belt rollersthat are rotatable around the axis parallel to the width direction, anda strip-shaped belt stretched over the plurality of belt rollers, andthe power transmission mechanism comprises a counter roller that isrotatable around the axis parallel to the width direction, and an outerperipheral surface of the counter roller is in contact with the beltroller or the belt and the roller.